Nervous-System Responses of Rats to Subchronic Inhalation of n-Hexane and n-Hexane + Methyl-Ethyl-Ketone Mixtures

摘要

The nervous system effects of continuous inhalation exposures to concentrations of n-hexane (110543) (HEX) or HEX plus methyl-ethyl-ketone (78933) (MEK) mixtures were investigated in male Wistar-rats. Long term effects of intermittent exposures to the mixtures were also examined in experiment-B. Solvent exposed animals from experiment-A showed marked reductions in weight. Those treated with the mixture of compounds demonstrated excessive hypersalivation, frequent orange/red discoloration of the skin and fur, and narcosis. All solvent exposed animals demonstrated limb weakness commencing by evasion of the hindlimbs and resulting in paralysis. Histological examination showed, axonal lesions in peripheral nerves, and in the gracile tract at cervical levels of the spinal cord. Those who survived experiment-B did not give evidence of narcosis and no depressed body weights were evident. Fur discoloration was restricted to an orange/red collar around the neck and appeared more often in animals exposed to the mixture than to hexane alone.